How to compress WebM videos
- Drop your .webm file.
- Keep WebM selected, or choose MP4.
- Pick a quality or target size.
- Compress and download.
When to keep WebM and when to switch to MP4
WebM with VP9 is roughly 20–30% more efficient than H.264 at the same quality and is ideal for websites. MP4 is the safer choice for iPhones, older TVs, editing software and messaging apps. ShrinkVid automatically uses about 25% less bitrate for VP9 at the same quality level.
Compressing screen recordings
Screen recordings contain lots of static content, so they compress very well. Use Low quality at the original resolution to keep text readable — reducing resolution makes small text blurry faster than lowering bitrate does.
Private by design
ShrinkVid never uploads your files. The page loads once, then all decoding and encoding happens on your device using the browser’s built-in WebCodecs API (hardware-accelerated video) and WebAssembly image codecs. That makes it safe for personal, confidential or work files — and there is no queue, no file size cap and no watermark. Read how it works.
Frequently asked questions
Are my files uploaded to a server?
No. ShrinkVid runs entirely in your browser. Files are read and encoded on your own device with WebCodecs and WebAssembly, so nothing is uploaded, stored or seen by anyone else. You can even disconnect from the internet after the page loads and it keeps working.
Why does VP9 encoding take longer?
Many devices have hardware encoders for H.264 but not VP9, so VP9 may be encoded in software, which is slower. Choose MP4 if speed matters more than size.
Is it really free? Is there a watermark or file size limit?
It is completely free with no watermark, no sign-up and no server-side file size limit. Because processing happens on your device, the only practical limits are your device’s memory and speed.
Last updated · by the ShrinkVid team